ID Mask Blur for Hidden Mesh Light

Hiya I am using Cycles Blender 2.71
Can someone help me with making a light bloom effect with a hidden Light mesh. I now how to use the node system to make an overall scene Bloom, I know about Index Pass numbers and ID masks but I am having trouble because the Sphere is hidden from the camera. Is it possible to do?

I realise this post hasn’t been on long but after the amount of views this has had I am guessing no one knows. So where would be the best place to ask this question?

I have no idea what you asking. What is a light bloom effect, can you explain or show an image of what your talking about?

I can do better than that Bloom is I believe the proper term for Glow

Lamp on another layer then use primary layers index pass to obstruct the lamp (if any occlusions occur) apply glow to this matte-ed lamp layer and add over the primary pass.

Oh that is cleaver I love that answer 3pointEdit thanks I will give that I try cheers, I really am impressed with Blender.

Just reporting back to say thank you, that worked a treat.